Different types of wipe areas and driving devices are known for cleaning windshields of motor vehicles. With respect to wipe areas, distinctions are mainly made between single-arm wipe areas and dual-arm wipe areas. In dual-arm wipe areas, the wiper arms of the wipers may be operated in tandem or in opposition.
Even in the case of two wipers, the drive device generally uses only one wiper motor whose rotary drive movement of its driven shaft is translated into an oscillating swivel motion of the drive shafts of the wipers via a spatial crank drive. Newer wiper motors are provided with electronics which regulate a reversing drive movement of the driven shaft. The electronics also allow a control of the wipe angle including a dynamic, load-dependent wipe-angle correction and wiping-speed regulation, thereby producing a larger nominal wiped area on the windshield. Furthermore, the electronic system allows different wipe functions and positions, such as an extended parking position, a service position for changing a wiper blade, an interval parking position and an alternating parking position for relieving the load on the wiper blades.
The wiper motors having an electronic system are provided with a control device including sensors for regulating the position and speed of the driven shaft and a micro-controller for detecting the position of the driven shaft. This leads to higher expenditures for the control device and requires additional space in the hood.
Wiper systems using opposed wipers are often used for wiping larger windshields. If these systems are driven by a wiper motor, a large size in accordance with the vehicle width results and a large space in the center of the vehicle. Also, the kinematic design with or without intermediate bearing is complicated and necessitates a large, high-capacity wiper motor. The many individual mechanical components produce large static wipe-angle tolerances in addition to dynamic wipe-angle tolerances which are caused by elasticities of the mechanical components and of the components of the support and fastening elements.
In order to obtain a less complex kinematic design and, thus, smaller wiping-angle tolerances, wiper systems using two wiper motors are utilized, which are located in the area of the wiper bearings and, therefore, do not require space in the center region of the windshield. Two synchronously running wiper motors having electronic communication are used for the driving. To satisfy the high demands placed on the wiper system in connection with synchronous running, safety and reliability, collision freedom, and also the security concept and emergency function, each wiper motor is provided with a full electronic system. Wiper motors are preferably regulated in reversing operating so as to obtain the advantages associated therewith.